The present invention relates to a sheet distribution method for performing sheet distribution operations such as collating and sorting and, more particularly, relates to a display control system for a copying machine equipped with a plurality of collating apparatus or collators.
Generally, a collator includes a sheet conveyance path, a plurality of sheet storage bins and a deflecting device which is movable to deliver sheets into the bins. This type of collator is usually designed for selective operation in any one of collation and assortment modes as desired. The collation mode refers to an operation mode wherein sheets on the same page are delivered one by one into different bins whereas the assortment mode refers to an operation mode wherein a given number of sheets are fed out continuously into a certain bin and then into the next bin when the first bin becomes full. Despite that the number of available bins is limited, it is sometimes desired to collate or assort a relatively large number of volumes which exceeds the total number of bins. In such a case, the input apparatus associated with the collator as typified by a copying or printing machine should preferably process all the volumes of sheets as one sheet feed cycle without any dwell in its operation. With these in view, it has been a common practice to connect some collators in series with the input apparatus and use them such that sheets are supplied to the first collator, then to the second when the capacity of the first is reached, then to the third when the capacity of the second is reached and so on.
Series connection of multiple collators will in this way facilitate collation or assortment of large numbers of volumes. However, this requires a disproportionate cost and a disproportionate space for installation since it is quite rare to process such large numbers of volumes in ordinary office work. Usually, what determines the least possible number of collators connected together is the user's judgement concerning the range of volumes which they deal with most frequently. The number of interconnected collators is thus dependent on the user. Considering the tendency to the use of the least number of collators and the number which depends on the user, it is desirable to uniformalize the manners of handling copiers and collators and to use the limited number of collators efficiently for collation or assortment even though the intended number of volumes may exceed the total number of bins of interconnected collators.
Where "Q" collators are interconnected in series and each collator has "B" bins therein, the total number of bins in the collators is expressed as BQ and this is usually the ability of all the interconnected collators for one time of collation or assortment (total processing ability). Commonly, some of the "Q" collators are empty with no sheets loaded in their bins. This condition may exist when the last operator interrupted collation or assortment halfway or when he failed to remove copy sheets from the bins of the collators after collation or assortment. Supposing that "q" collators of the "Q" collators are empty, the total number of bins of the empty collators or their effective processing ability is Bq.
Thus, a storage register is employed to store a designated number of volumes N to be collated irrespective of the total processing ability of collators. Collation data N in this register is compared with the total processing ability BQ and effective processing ability Bq. If the data N is smaller than the effective processing ability of the collators, copy sheets will be collated using the empty collators. When the data N is smaller than the total processing ability BQ but larger than the effective processing ability Bq, the empty collators will be used to perform multiple times of repeated collation. When the effective processing ability Bq is zero meaning that no empty collators exist, collation will not be performed. It should be born in mind that, though not described herein, the copying machine is operable even if collation or assortment does not occur. Furthermore, where the data N in the register is larger than the total processing ability of the collators, collation or assortment will preferably be carried out if there is any effective processing ability Bq and not if the effective processing ability Bq is zero. In this instance, visual indication for the operator is important in simplifying handling of the system. Where the collation data is larger than the total processing ability BQ but smaller than the effective processing ability Bq, it is unadvisable in view of the document replacement to process the desired number of volumes by dividing them into multiple groups if the effective processing ability is not zero. This is because, in the case of collation, after the first collation wherein copy sheets on determined pages are repeatedly delivered, the same pages of documents need be replaced by one another for the second collation for the remaining volumes. Thus, as an alternative to such a method, collation may not be performed when the number of desired volumes is less than BQ but larger than Bq. However, that collation is disabled even when all the collators are empty is contradictory to general needs; this is an exceptional case wherein collation will be performed repeatedly by dividing the desired number of volumes. Again, the display for the operation is of consequence with a view to simplifying the handling of the system.